Two areas of interest are pursued using cultures of endothelial cells. In one line of work, the link between cigarette smoking and coronary artery disease is being examined by investigating lipoprotein derived cholesterol uptake and metabolism in cells exposed to carbon monoxide, a constituent of cigarette smoke. The other direction of study involves measuring the flux of low density lipoproteins through intact, confluent monolayers of endothelial cells, and then examining the effects of various perturbations on this permeability.